Spray nozzle having a rectangular high velocity gas outlet and low velocity liquid outlets



3,199,789 Y GAS J. R. JAMES Aug. 10, 1965 SPRAY NOZZLE HAVING ARECTANGULAR HIGH VELOCIT OUTLET AND LOW VELOCITY LIQUID OUTLETS 2Sheets-Sheet 1 Filed July 22, 1963 lllllll l INVENTOR.

JAMES R. JAMES BY wfly/i;

ATTORNEY Aug. 10, 1965 J. R. JAMES SPRAY NOZZLE HAVING A RECTANGULARHIGH VELOCITY GAS OUTLET AND LOW VELOCITY LIQUID OUTLETS Filed July 22,1965 2 Sheets-Sheet 2 /2 \nl gaw 0 000 :OOOOOOO lnv In .0009009009 00-INVENTOR.

JAMES R. JAMES [@fifi ATTORNEY United States Patent C) M 3,199,789 SPRAYNfiZZLE HAVHJG A RECTANG' .QAR HIGH VELOCITY GAS @UTLET AND LEW VELGCITYLIQUID OUTLETS .iames R. James, Louisville, Ky., assignor to The l/iartin Sweets Company, inc Louisville, Ky, a corporation of KentuckyFiled July 22, 1963, Ser. No. 296,724 4 Claims. (Cl. 239-424) Thisinvention relates to a novel spray nozzle for use in spraying a liquidstream which is conveyed by a pressurized gas. More specifically, thisinvention relates to a spray nozzle which is adapted to spray a liquidstream comprising mixed liquid components in which one or more of saidcomponents may contain suspended solids. More specifically, thisinvention relates to a spray nozzle which is adapted to produce anelliptical spray pattern on a substrate.

The spray nozzle of this invention is specifically adapted for use inspraying various foam blends, as for example, polyrethane. However, itmay be advantageously used in spraying other liquid components whereinthe problem of overspray and the production of a uniform pattern ofuniform thickness is encountered. Overspray, which is sometimes termedoff spray, relates to materials which fall outside of the general spraypattern. Additionally, overspray relates to particles of materials whichdo not reach the surface of the substrate. Thus, if the atomization ofthe material is too great there is a possibility of a large portion ofthe liquid material being so line in particle size that is not conveyedto the substrate and either falls short or is blown away by cross draftor the exhaust system in the spray booth. Gverspray refers also tovolatile components in the stream which turn into a gas prior toreaching the substrate and thus are effectively lost.

An object of my invention, therefore, is the provision of a spray nozzlewhich minimizes the amount of ofispray.

Another problem which is encountered in the spraying of foam blends ontoa substrate is in obtaining a uniform desired thickness. In spraying offoam blends thicknesses of from a fraction of an inch up to severalinches are desired and this normally creates a difficulty in producingan even planar surface. In some instances, thicknesses up to ten inchesor more are required. In some cases, the exterior surface appears roughand pebbly. More importantly, however, with prior art apparatus, therehas been a lack of uniformity in thickness of the sprayed material. Thisproduces waste material on the thicker portions if one thickness isdesired to accomplish the purpose of coating and/or insulation. Thus,for example, if a thickness of one inch of insulation is required, itwas sometimes necessary with prior art apparatus to spray an average ofone and one-quarter to one and one-half inches to insure that in certainareas there would be a minimum of one inch.

Another important object of my invention is the provision of a spraynozzle which will provide a uniform pattern whereby a uniform thicknessof material may be sprayed onto a substrate.

The nozzle of my invention may be utilized on some types of mixing headsnow in production. One such type of mixing head is commercially producedby The Martin Sweets Company, Inc. of Louisville, Kentucky. This type ofmixing head is described by John F. Reeves in an article entitled, RigidFoamsApplication and Use in Transportation, contained in thepublication, Cellular PlasticsTodays Technology, which was presented atthe 7th Annual Technical Conference Proceedings, Cellular PlasticsDivision, Society of the Plastics Industry, and published by the Societyof the Plastics Industry,

3,199,789 Patented Aug. 10, 1965 Inc., New York, New York, Section 2N,pages 2 through 6, April 1963. This mixing head utilizes a rotatablerodtype valve such as that disclosed by G. F. Spragens in US. Patent3,098,596 for Valve Packing Assembly. By use :of this valvecommunication is established in one position to the mixing chamber ofthe mixing head and in another position to return lines forrecirculation of the liquid components by liquid pumps. Thus, the liquidcomponents, as for example, a prepolymer mixture and a catalyst, aremixed internally in the mixing chamber so that the provision of myimproved nozzle with an accessory source of gas will provide a sprayingapparatus for use on various substrates, which may be disposed eithervertically or horizontally.

Basically, my invention provides a gas pattern forming means whereby agas pattern of high velocity and low pressure is formed directlyadjacent to the face of the nozzle. Combined with the high velocity gaspattern is a low velocity liquid flow which is pushed by atmosphericpressure or, more precisely, by the difference in atmospheric pressureand the low pressure zone created by the high velocity gas into the gaspattern to be conveyed onto the substrate. Additionally, I have found itadvantageous to utilize a liquid distribution face directly adjacent tothe gas pattern forming means and the liquid outlets so that the liquidwill be pushed up onto the liquid distribution face in the form of auniform layer to be aspirated into the gas stream. The low pressure,high velocity gas pattern is provided by a series of small diameter gasoutlets arranged in such a manner as to produce a gas pattern which isrectangular in shape and of small cross section directly adjacent to theface of the nozzle. In one modification, I have used a single row ofsmall diameter gas outlets. The pattern formed thereby is considered tobe rectangular in shape and of small cross section. The low velocityliquid flow is accomplished by use of relatively large liquid outletsdisposed on each side of the gas pattern forming means. The liquiddistribution face is disposed on either side of the gas pattern formingmeans between the gas outlets and the liquid outlets, so that the liquidis first distributed over the distribution face prior to atomization bythe gas stream. I have found that it is advantageous to make both thegas pattern forming means and the liquid distribution face longer thanthe liquid outlets to insure that all of the liquid is drawn onto thesides of the face. Furthermore, in a preferred embodiment I utilizeslit-like liquid outlets to assist in dis tributing the liquid over arelatively long area. I have found that if the liquid projects in theform of a stream away from the nozzle to meet the gas stream, thatconsiderable turbulence results, thus producing an excessive amount ofoverspray. Thus, one of the features of my invention is the mixing ofthe liquid and the gas in an area adjacent to the face of the nozzle andnot in spaced relation therefrom.

ly invention will be better understood by reference to the accompanyingdrawings and to the following detailed description.

FIG. 1 is a front elevation of the spray nozzle of this invention.

PEG. 2 is a side elevation of the nozzle.

FIG. 3 is a horizontal section of the nozzle of this invention takenalong lines 33 of FIG. 1.

FIG. 4 is a diagrammatical view illustrating the relation of the liquidoutlets and the gas outlets of my spray nozzle to the pattern producedon the substrate.

FIG. 5 is a front elevation of another embodiment of my spray nozzle.

FIG. 6 is a horizontal section taken along lines 66 of PEG. 5.

FIGS. 7 and 8 are front elevations of other modifications of my spraynozzle.

amazes 3 Referring now to an illustration of the embodiments of myinvention as shown in FIGS. l3, 1 designates the spray nozzle. The faceof the nozzle 15 contains a raised enclosure 8 for the liquid andgaseous outlets 9 and 4, respectively. Gas is introduced through gashose 25, which is connected to the nozzle by hose coupling 26, and

into gas conduit 2 which runs transversely across the diameter of thenozzle and terminates in plug 27. Conduit 2 communicates with airchannels 3, the axes of which are substantially perpendicular to theconduit, and to the face 15 of the nozzle. The air channels 3 terminatein air outlets 4 which in FIG. 1 are in approximate linear arrangementalong ridge 5 in two rows separated by septum 7. The liquid component isintroduced through liquid chamber 11, which has sloping walls 17 whichconverge with liquid channels it Liquid channels it terminate inslit-like liquid outlets 9 on each side of the walls 6 of ridge 5. Theseslits are of such size that the liquid leaves the slits at a very lowvelocity, otherwise the liquid would shoot out some distance beforebeing drawn into the gas stream, causing a tremendous amount ofoverspray. Further, it will be noted that the walls 6 of ridge 5 extendbeyond the ends of the slits 9 to form a liquid. distribution face, sothat the liquid emerging therefrom at low pressure and low velocity isdrawn up the walls 6 of the ridge in a uniform layer and is thencepushed into the low pressure gas stream. Liquid chamber 11 is separatedin the middle by a V-shaped post 16 in which air conduit 2 is located(see FIG. 3). The entire assembly is equipped with flange 12 and groove13 on the inner side for an O ring seal so as to engage with the mixinghead of the type previously referred to.

In the modifications shown in FIGS. 5 and 6, the liquid channelsterminate in round liquid outlets 3!). Gas outlets 4 are contained in atriangular ridge 37 in which the area 35 constitutes a liquiddistribution face and area 36 serves as a dividing septum.

In the modification shown in FIG. 7, the liquid outlets comprise aseries of round openings 31 and the gas outlets 4 form a single rowalong the face of the ridge. This modification is primarily useful withmaterials falling in the lower range of viscosities.

FIG. 8 illustrates another modification utilizing two round liquidoutlets 32 on each side of the ridge 5.

Operation For purposesof illustration, the operation of the nozzle ofthis invention is as follows: If it were desired to produce' a foamblend, the mixed chemical constituents in the form of one or moreliquids in which one or more of the constituents might contain asuspended solid, enter liquid chamber 11. The mixed components flowthrough liquid channels and emerge from liquid outlets 9. Compressed gasat a pressure generally in the range of from. to 100 p.s.i.g. isintroduced via air hose 25 onto conduit 2 and is forced through airchannels 3 to emerge from air outlets 4 as small gas jets of highvelocity. These air channels in practice are about 4 of an inch indiameter although the diameter may vary somewhat depending on theparticular requirements. Thus, there is produced a low pressure areaprojecting from the longitudinal axis of the nozzle, the shape of thisarea, in the zone adjacent to the face of the ridge is substantiallyrectangular, having a very narrow cross section. The liquid componentsemerging at a relatively low pressure and velocity from liquid outlets 9are aspirated into the low pressure zone produced by the high velocitygas stream. More precisely, atmospheric pressure or the differencebetween atmospheric pressure and the low pressure zone caused by the gasjets, forces the liquid against the distribution wall 6 of ridge 5 toforce the liquid components into the gas pattern. The pattern at thispoint is generally rectangular and thus differs from that which resultson thesubstrate. It appears that the liquid entering the gas streamcauses turbulence so directed that it confines itself for most part toone of the two axes perpendicular to the direction of spray; thusspreading the original pattern composed only of gas to form an ellipseof approximately two to one dimensions (see FIG. 4). it will be notedthat the longitudinal or major ams of the pattern 2% is essentiallyperpendicular to the longitudinal direction of the air outlets. Thematerial 21 outside of the pattern area 26 is overspray previouslyreferred to.

I have found that the relation of the minor axis of the ellipse to themajor axis of the ellipse as it appears on the substrate isapproximately one to two. Moreover, utilizing various liquidconstituents having viscosities within the approximate range of fromless than 1 centipoise to about 5,000 centipoises it has been found thatthe pattern produced is similar in all cases. \Vhile the shape of thepattern and its relation on the substrate relative to the face of thenozzle appears similar, the pattern does not to be the same size undervarious conditions and with different materials. My experiments showthat the higher the throughput of the liquids the bigger the patternbecomes. However, the ratio of the major axis to the minor axis appearsto remain about two to one. I have utilized materials ranging inviscosity from less than 1 centipoise to about 5,000 centipoises, i.e.,from methylene chloride to a viscous foam blend of polyurethane. Itappears also that the hi her-the viscosity of the liquid the big er thepattern on the substrate. Thus, it may be stated that the moreturbulence which is created in the spray pattern, the larger the patternon the substrate will be. it will be appreciated that the pattern underdiscussion is that obtained at the usual spray distance of two to fourfeet from the gun to substrate. Under a different set of circumstances,moving the gun closer to the substrate causes the propelling gas todeform the spray already on the substrate. Moving farther away from thesubstrate causes the atomized foam, or a portion thereof, to fall shortof the substrate. However, it may be stated that even though there arewide variations in the dimensions of the pattern depending upon thethroughput of the liquid, the viscosity, and the distance fromthesubstrate, that the resulting pattern has a ratio of the major of thepattern to the minor axis of the pattern of about two to one. It shouldalso be pointed out that the major axis of the pattern on the substratelies perpendicular to the longitudinal direction of the air outlets onthe face of the nozzle.

While there has been shown and described the fundamental novel featuresof the invention as applied to preferred embodiments, it will beunderstood that various omissions and substitutions and changes in theform and details of the assembly illustrated and in its operation may bemade by those skilled in the art without departing from the spirit ofthe invention. It is the intention, therefore, to be limited only so asto be commensurate in scope with the appended claims.

I claim:

1. In a liquid spraying appliance wherein a liquid com ponent isconveyed by a pressurized gas stream:

(a) a nozzle for producing a substantially elliptical spray pattern on asubstrate, said nozzle having a face portion located in a plane andcontaining a gas pattern forming means and liquid channels having liquidoutlets which open in the face portion of said nozzle inwhich (i) saidgas pattern forming means comprises a gas channel containing a highvelocity gas outlet which opens near the center of the face of saidnozzle in the form of a jet opening of relatively small dimension andwhich is in operative relation with a source of pressurized gas to forma low pressure area which defines a substantially rectangular gaspattern of narrow cross section in close proximity to said face LALVportion of said nozzle, said gas channel having.

an axis which lies essentially perpendicular to the plane of the face ofsaid nozzle and which lies essentially parallel to the longitudinal axisof said nozzle; and

(i) said liquid channels terminate in low velocity liquid outlets oflarge dimension relative to the dimension of said high velocity gasoutlet which are located on each of two sides of said gas patternforming means in the face portion of said nozzle, said liquid channelsbeing in operative relation to a source of liquid so as to produce atleast two liquid streams of low velocity which are aspirated into saidgas pattern in an area outside of said nozzle out which is closelyadjacent to the face portion of said nozzle.

2. A nozzle as defined in claim 1 in which the gas pattern forming meanscomprises at least one linearly arranged series of small diameter highvelocity gas outlets located near the center of the face portion of thenozzle so as to produce a gas pattern, in close proximity to the faceportion of the nozzle, which is substantially rectangular in shape andwhich has a narrow cross section.

3. A nozzle as defined in claim 1 in which the gas pattern forming meanscomprises a series of high velocity gas outlets of small diameter whichopen along the surface of a raised ridge running across the center ofthe face of the nozzle, said ridge projecting forwardly of the plane ofsaid face portion in the direction of the longitudinal axis of saidnozzle, said series of high velocity gas outlets forming a pattern ofgas outlets longer in one dimension than in another in which the longdimension of said pattern extends beyond the ends of the liquid outlets.

4. A nozzle as defined in claim 1 which is further combined with araised step running across the center of the face portion of the nozzle,said step projecting forwardly of the face portion in the d-irection ofthe longitudinal axis of said nozzle and terminating in a flat surface,said high velocity gas outlet of said gas pattern forming means openingin the fiat surface of said raised step, and the sides of said raisedstep forming two liquid distribution faces, each of said faces beinglocated directly adjacent and laterally to said gas pattern formingmeans and each of said faces lying directly adjacent and medially to oneof said liquid outlets.

References Qited by the Examiner UNITED STATES PATENTS 584,864 6/97Fisher 239424 1,733,054 10/29 Crill 239424 2,382,151 8/ Harper 239--4242,515,792 7/50 Ofeldt 239-9 2,721,148 10/55 Reading 239-9 2,813,75412/57 Zielinski 239-424 3,084,875 4/63 Klingler 239-424 3,096,023 7/63Thomas 239424 FOREIGN PATENTS 583,788 6/ 47 Great Britain.

M. HENSON WOGD, IR., Primary Examiner.

EVERETT W. KIRBY, Examiner.

1. IN A LIQUID SPRAYING APPLIANCE WHEREIN A LIQUID COMPONENT IS CONVEYEDBY A PRESSURIZED GAS STREAM: (A) A NOZZLE FOR PRODUCING A SUBSTANTIALLYELLIPTICAL SPRAY PATTERN ON A SUBSTRATE, SAID NOZZLE HAVING A FACEPORTION LOCATED IN A PLANE AND CONTAINING A GAS PATTERN FORMING MEANSAND LIQUID CHANNELS HAVING LIQUID OUTLETS WHICH OPEN IN THE FACE PORTIONOF SAID NOZZLE IN WHICH (I) SAID GAS PATTERN FORMING MEANS COMPRISES AGAS CHANNEL CONTAINING A HIGH VELOCITY GAS OUTLET WHICH OPENS NEAR THECENTER OF THE FACE OF SAID NOZZLE IN THE FORM OF A JET OPENING OFRELATIVELY SMALL DIMENSION AND WHICH IS IN OPERATIVE RELATION WITH ASOURCE OF PRESSURIZED GAS TO FORM A LOW PRESSURE AREA WHICH DEFINES ASUBSTANTIALLY RECTANGULAR GAS PATTERN OF NARROW CROSS SECTION IN CLOSEPROXIMITY TO SAID FACE PORTION OF SAID NOZZLE, SAID GAS CHANNEL HAVINGAN AXIS WHICH LIES ESSENTIALLY PERPENDICULAR TO THE PLANE OF THE FACE OFSAID NOZZLE AND WHICH LIES ESSENTIALLY PARALLEL TO THE LONGITUDINAL AXISOF SAID NOZZLE; AND (II) SAID LIQUID CHANNELS TERMINATE IN LOW VELOCITYLIQUID OUTLETS OF LARGE DIMENSION RELATIVE TO THE DIMENSION OF SAID HIGHVELOCITY GAS OUTLET WHICH ARE LOCATED ON EACH OF TWO SIDES OF SAID GASPATTERN FORMING MEANS INTHE FACE PORTION OF SAID NOZZLE, SAID LIQUIDCHANNELS BEING IN OPERATIVE RELATION TO A SOURCE OF LIQUID SO AS TOPRODUCE AT LEAST TWO LIQUID STREAMS OF LOW VELOCITY WHICH ARE ASPIRATEDINTO SAID GAS PATTERN IN AN AREA OUTSIDE OF SAID NOZZLE BUT WHICH ISCLOSELY ADJACENT TO THE FACE PORTION OF SAID NOZZLE.